A typical veneer lathe, which represents the environment for the present invention, is a dual spindle machine having a pair of axially spaced headstocks mounted on a common bed. A veneer knife is mounted on a knife support frame which is in turn is mounted on a knife carriage. This knife carriage is driven along parallel guidelines extending transversely of the spindle axis. The veneer lathe also includes one or more backup rolls adapted to preclude deflection of the log or block during the veneer peeling operation.
In the cutting process, lathes are equipped to detect the approximate diameter of an incoming block and retract the knife carriage automatically to clear the wood by several inches. To initiate the cut, the knife carriage is advanced cautiously until the highest protruding wood engages the knife, then locked into an advanced feed rate of approximately double veneer thickness. As a result of the uneven block surface, the veneer initially peeled creates what is known as "trash" or "round-up" veneer that is not suitable for commercial use. This trash veneer initially produced is directed through an opened trashgate and on to a chipper. When a minimum sheet of usable veneer is detected, the knife and knife carriage will abruptly leave the cut. The "trash" veneer is allowed to clear the production line, then the trashgate is closed. At that time the knife is advanced at a single peel thickness rate to peel the block to its core. The lathe will initially produce veneer of various sizes, called "random " veneer, until it begins to produce the full-sheet veneer. The random veneer is directed to a clipper and green chain, and the full sheet veneer is directed to production stackers.